The present disclosure relates to contactless interface devices, and more particularly relates to anti-collision coupling for contactless interface devices. An anti-collision coupling for contactless interface devices is provided.
Contactless integrated circuit (IC) cards and radio frequency (RF) identification (RFID) cards are types of contactless interface devices known as contactless cards. In such contactless cards, an interface coupling or information exchange may be accomplished when the contactless cards come within range of a contactless card reader.
If more than one contactless card approaches a reader at the same time, there may be confusion in the reader because of multiple concurrent signals from each card. To alleviate such confusion, an anti-collision interface coupling method is used to identify the cards that approach the reader.
The anti-collision coupling methods for contactless cards are typically divided into close coupling methods and remote coupling methods, according to the desired approach distance between a card and a reader. In addition, the remote coupling methods are typically divided into proximity, vicinity and RF methods.
An example of a close coupling method (CICC) is set forth in the ISO 10536 standard, as known in the art. Examples of proximity coupling methods (PICC) are set forth in the ISO/IEC 14443 standard, as also known in the art. An example of a vicinity coupling method (VICC) is set forth in the ISO/IEC 15693 standard, as further known in the art.
The PICC methods defined in the ISO/IEC 14443 standard include a type A coupling method and a type B coupling method. For the type A method, the anti-collision method of the contactless cards that satisfy the ISO 14443 type A standard make use of a Unique Identification (UID), which each card has separately. When the contactless cards approach an effective region of the reader, the contactless cards each generate a signal to indicate their presence, the reader requests a card to transfer its UID, the card transfers the UID to the reader by unit, and the reader identifies the card by comparing the UID separately. The ISO 14443-A standard uses a UID method and a bit collision method, where the card is required to respond within a precise response time. Unfortunately, it takes the card a long time to respond because of the bit unit identification required within each card.
For the type B method, the anti-collision method of the contactless cards that satisfy the ISO 14443 type B standard makes use of an optional value called a Pseudo Unique Proximity card Identifier (PUPI), which each card generates separately. When the contactless cards approach an effective region of the reader, the reader requests the cards to generate a random value having a set scope, the cards each generate PUPI values different from each other, and the reader selects a card by calling one of the received PUPI values. In the ISO 14443-B standard, the card must generate a random value within a fixed range and the reader must generate slots. Unfortunately, this process takes a long time because of the card operation required within each card.
For the vicinity method, the anti-collision method of the contactless cards that satisfy the ISO 15693 standard makes use of a Unique Identification (UID), which each card has separately. When the contactless cards approach an effective region of the reader, the reader generates a slot having sixteen values whenever an EOF occurs. The reader requests a card to transfer a UID and recognizes the card by noting that the card responds to a slot that has the same value as its UID. The ISO 15693 standard uses a UID method, where the reader must make 16 slots. The card responds to the corresponding slot when the UID is in accord with the slot. The card compares its UID with the slots 0 to 16, and counts the slot whenever the EOF occurs. Unfortunately, this process takes a long time because of the card operation required within each card. Thus, conventional methods for anti-collision coupling suffer from the disadvantage that a complex arithmetic operation is required within each card. The above and other drawbacks and disadvantages of the prior art are addressed by an anti-collision coupling for contactless cards in accordance with exemplary embodiments of the present disclosure.